A thermometer that measures the incessantly changing temperature of an engine during running of a vehicle, digitizes the result of measurement, and displays the temperature is not incorporated in a racing two-wheel or four-wheel vehicle (including a cart). When it says that the temperature of an engine is measured, it signifies that the temperature of an engine main unit including cylinders is directly measured using a sensor. Otherwise, it signifies the measurement of the temperature of a radiator which cools cooling water heated by the engine or the measurement of the temperature of a cooling water flowing through a water pipe linking a water jacket, which encloses the cylinders, and the radiator. Otherwise, it signifies the measurement of the temperature of oil that is reserved in an oil pan located below the engine main unit and that flows through a circulation path.
By the way, managing the temperature of the engine during racing is very important in order to allow the engine to operate efficiently so as to attain a predetermined vehicle speed on a stable basis. Through the temperature management, occurrence of a fault such as the overheating of the engine or the seizure of a piston or a valve accompanying the overheating can be avoided.
Moreover, during racing, a transmission gear must be shifted based on the running speed of a vehicle or a road condition as well as an engine speed. A driver must perform this action by intuition.
However, a conventional two-wheel or four-wheel vehicle does not include a thermometer that indicates the incessantly changing temperature of an engine while measuring it. A driver must trust his/her intuition so as to accelerate the vehicle by stepping on an accelerator pedal or to shift a transmission gear by handling a shift level. Consequently, the performance of the engine may not be fully drawn out but the vehicle may be driven in a high-fuel consumption and high-noise condition. Moreover, when an engine speed is too high, that is, when the engine is overheated, if the transmission gear is shifted, a relatively small mechanical stress applied to the engine, a transmission, or a clutch may bring about a critical damage.
Accordingly, an object of the present invention is to provide a thermometer for an engine of a vehicle that is optionally incorporated in a vehicle such as an existing two-wheel or four-wheel vehicle, and that can readily measure and display the incessantly changing temperature of an engine during running of the vehicle. Thus, the vehicle can be driven in an optimal situation in which no stress is applied to the engine. When the measured temperature of the engine exceeds a set value, a warning indication is given so that, for example, an acceleration lever can be handled in order to restore the engine to an optimal driven state or restore the vehicle to an optimal driven state.